/*******************************************************************************
 * Copyright (c) 2004, 2014 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.resources;

import org.eclipse.che.core.internal.preferences.ChePreferences;
import org.eclipse.core.internal.preferences.EclipsePreferences;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.core.runtime.preferences.IScopeContext;

import java.util.concurrent.ConcurrentHashMap;

/**
 * Object representing the project scope in the Eclipse preferences
 * hierarchy. Can be used as a context for searching for preference
 * values (in the <code>org.eclipse.core.runtime.IPreferencesService</code>
 * APIs) or for determining the correct preference node to set values in the store.
 * <p>
 * Project preferences are stored on a per project basis in the
 * project's content area as specified by <code>IProject#getLocation</code>.
 * </p><p>
 * The path for preferences defined in the project scope hierarchy
 * is as follows: <code>/project/&lt;projectName&gt;/&lt;qualifier&gt;</code>
 * </p>
 * <p>
 * This class is not intended to be subclassed. This class may be instantiated.
 * </p>
 * @see IProject#getLocation()
 * @since 3.0
 */
public final class ProjectScope implements IScopeContext {

	/**
	 * String constant (value of <code>"project"</code>) used for the 
	 * scope name for this preference scope.
	 */
	public static final String SCOPE = "project"; //$NON-NLS-1$

    private static ConcurrentHashMap<String, IEclipsePreferences> cache = new ConcurrentHashMap<>();

    private IProject context;

    /**
     * Create and return a new project scope for the given project. The given
     * project must not be <code>null</code>.
     *
     * @param context the project
     * @exception IllegalArgumentException if the project is <code>null</code>
     */
    public ProjectScope(IProject context) {
        super();
        if (context == null)
            throw new IllegalArgumentException();
        this.context = context;
    }

    /*
	 * @see org.eclipse.core.runtime.IScopeContext#getNode(java.lang.String)
	 */
    public IEclipsePreferences getNode(String qualifier) {
        if (qualifier == null)
            throw new IllegalArgumentException();

        if(!cache.containsKey(context.getName())){
            synchronized (ProjectScope.class){
                if(!cache.containsKey(context.getName())){
                    String pathToWorkspace = ResourcesPlugin.getPathToWorkspace();
                    IPath fullPath = context.getFullPath();
                    cache.putIfAbsent(context.getName(), new ChePreferences(pathToWorkspace + fullPath + "/.codenvy/project.preferences"));
                }
            }
        }
        return cache.get(context.getName());
    }

    /*
	 * @see org.eclipse.core.runtime.preferences.IScopeContext#getLocation()
	 */
    public IPath getLocation() {
        IProject project = ((IResource)context).getProject();
        IPath location = project.getLocation();
        return location == null ? null : location.append(EclipsePreferences.DEFAULT_PREFERENCES_DIRNAME);
    }

    /*
	 * @see org.eclipse.core.runtime.preferences.IScopeContext#getName()
	 */
    public String getName() {
        return SCOPE;
    }

    /* (non-Javadoc)
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (!super.equals(obj))
            return false;
        if (!(obj instanceof ProjectScope))
            return false;
        ProjectScope other = (ProjectScope)obj;
        return context.equals(other.context);
    }

    /* (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
    @Override
    public int hashCode() {
        return super.hashCode() + context.getFullPath().hashCode();
    }
}
